The present invention relates to a method of manufacturing a piezoelectric ink jet device having a flexible membrane a piezoelectric actuator mounted on the membrane, and a rigid substrate (distribution plate) attached to the side of the membrane carrying the actuator, wherein the rigid substrate is bound to a side of a carrier plate carrying the actuator, and material is removed from the carrier plate on the side opposite to the actuator, leaving only a thin layer of the carrier plate which then forms the membrane.
The ink jet device is used in an ink jet printer for expelling an ink droplet in response to an electric signal energizing the piezoelectric actuator. The actuator, when energized, causes the membrane to flex into the pressure chamber, so that the pressure of liquid ink contained in that chamber is increased and an ink droplet is ejected from a nozzle that communicates with the pressure chamber.
In a typical ink jet printer, the ink jet device takes the form of an array of a large number of nozzles and actuator units, where the nozzles are arranged with a very small pitch so as to achieve a high resolution of the printer. As a result, a manufacturing process is required which permits a high nozzle density of the ink jet device. Since the membrane and the actuator are subject to mechanical strains that vary with high frequency, the membrane must firmly and reliably be connected with both the actuator and the rigid substrate.
In a known manufacturing process, the membrane is secured at the substrate by anodic bonding. This, however, has the drawback that the actuator cannot be attached to the membrane prior to anodic bonding. Further, when the actuator is secured on the relatively thin flexible membrane, there is a considerable risk of damage.
US 2006/0049723 A1 discloses a method of the type indicated above, wherein the carrier plate includes a porous layer which separates the membrane from the rest of the plate, and the material is removed by mechanically destroying the porous layer.
US 2005/0046678 A1 discloses an ink jet device and a manufacturing process wherein electrode layers and piezoelectric layers forming the individual actuators are successively formed and patterned on the membrane.
US 2006/0176340 A1 discloses a manufacturing process for an ink jet device that is composed of a number of plate-like components that are stacked one upon the other and bonded together, one of the components being the membrane with the actuators formed thereon. The membrane and the various layers of the actuators are successively formed on a surface of a glass plate that has been coated with an adhesive layer and into which a plurality of through-holes have been created. A wiring pattern for electrically contacting the actuators is formed on a rigid substrate that constitutes another component of the device. These components are then bonded together. The adhesive layer on the glass plate is dissolved by means of a solvent that penetrates through the holes in the glass plate, so that the glass plate may be removed, leaving the actuators and the membrane attached to the substrate component.